<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
			<button id="button">按钮1</button>
            <button class="button">按钮2</button>
            <button name="button">按钮3</button>
            <button>按钮4</button>
            <button type="button">按钮5</button>
            <button>按钮6</button>
			<script type="text/javascript">
		var b1=document.getElementById("button");
		console.log(b1);
		var b2=document.getElementsByClassName("button");
		console.log(b2[0]);
		var b3=document.getElementsByName("button");
			console.log(b3[0]);
		var b4=document.getElementsByTagName("button");
		console.log(b4[3]);
		var b5=document.querySelector("button[type]");
		console.log(b5);
		var b6=document.querySelectorAll("button");
		console.log(b6[5]);
		</script>
	</body>
</html>
